On Wed, 13 Jan 1999, Ken Stuart wrote:
> On Tue, 12 Jan 1999 15:26:57 -0500, Todd Moody <[log in to unmask]> wrote:
>
> >This means that if we accept the Neanderthin premise that 12,000
> >or so years is not enough to cause reliable adaptation to
> >agricultural foods then we should also accept the conclusion that
> >there has not been enough time to adapt to New World foods.
> It seems to me that the flaw in this reasoning is that it assumes
> that first the environmental stimulus occurs, then the
> environmental adaptation occurs. However, Dr. Peter Dadamo
> points out that the mutations could occur long before the
> environmental stimulus, which then is favorable for the
> "mutants".
And he is correct. Environmental change doesn't cause mutations;
it only selects them.
The real challenge is to say with some precision what it means to
be adapted to a particular food. The Neanderthin view is that it
means that the proteins in that food are not recognized by the
body as "foreign"; i.e., they do not trigger an activation of the
immune system to defend against those proteins. Oddly enough,
D'Adamo says pretty much the same thing (at least, as far as the
lectin part of the theory is concerned).
Neanderthin says nothing about empirical testing for whether a
given protein is "foreign" for a given person. Instead, it uses
an approach that is at once a priori and probabilistic. That is,
given that certain foods entered the human food supply rather
late, the probability that our bodies would fail to identify its
proteins as foreign is low. The unstated assumption is that it
is long-term exposure to the proteins that eventuates in their
not being identified as foreign.
D'Adamo's theory, whether or not it is correct, has the advantage
of being laid out in more detail. First, he correctly points out
that agglutination (clumping) of cells is the phenomenon that
activates the immune response, i.e., mobilization of macrophages
to dispose of the agglutinated cells. If a protein does not
cause agglutination, then the immune system is not activated
(Note: Proteins can have other deleterious effects, such as
acting as poisons, without the immune system being involved).
D'Adamo claims that the tendency of a given lectin to agglutinate
blood cells depends mainly on ABO blood type. As far as I know,
we have only his own research to go on. He uses the ABO types,
as opposed to other blood typing systems, because the tissues of
the digestive tract share the ABO antigen characteristics. Thus,
it is his view that a lectin that causes blood cells to
agglutinate will also tend to cause agglutination of cells in the
digestive tract, which will in turn cause the immune system to
target those tissues, resulting in what we think of as an
"auto-immune" response. The immune system is not really
considering the cells of the intestinal wall as foreign but is
attempting to dispose of the agglutinated cells.
In evolutionary terms, even though the A, B, and O mutations may
have been present for millions of years, the O mutation dominated
as long as conditions favored it. As conditions changed, the
other blood types proliferated. On this way of looking at
things, "adaptation" is a statistical process in which
subpopulations become more or less common in the overall
population.
For people using Neanderthin or other versions of paleolithic
diet this is a very important topic. The set of pre-agricultural
foods does not correspond to any of D'Adamo's sets of
non-agglutinating foods for a particular blood type. This
doesn't show that D'Adamo's theory is wrong (as I once thought it
did), because there is nothing in evolutionary theory that says
that humans (or any other creature) must be perfectly adapted to
every item in their food supply. But if D'Adamo is correct then
it follows that some "paleo" foods, such as oranges, may
nevertheless be foods that activate the immune system in some or
all people. Some independent confirmation of D'Adamo's empirical
results would be very helpful.
Todd Moody
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